Optical burst switching (OBS) and optical packet switching (OPS) are a very advanced research area in the optical network field. However, only an extremely small part of the technology has been developed into solutions for a high-speed (peta-bits/second) broadband system suitable for real application requirements regarding performance, cost, power consumption, and so on.
The optical packet or optical burst switching is mainly classified into two hardware functions referred to as switch fabric and buffering, both of which utilize passive or active technology.
Here, most active technology enables complex optical signal processing using a semiconductor optical amplifier (SOA) and a wavelength converter, but this requires complex control, consumes much power, and needs rather complex device technology.
On the other hand, passive technology can overcome the drawbacks of the active technology but has a drawback with which wavelength conversion for wavelength continuity required in optical packet or optical burst switching systems is not provided for a wavelength division multiplexing (WDM) system schemes.
On the basis of such merits and demerits of the hardware functions, a new optical switching system in which a passive switching unit is combined with an active buffering unit has been suggested according to the conventional art.
The conventional optical switching system uses an asynchronous method of inputting optical data regardless of input time and data size rather than at a pre-determined time or in a uniform size. Thus, data collision frequently occurs, and many shared active buffers and optical wavelength converters are needed.